Epidermal N-acetylation of p-aminobenzoyl glutamic acid: difference in response to ultraviolet B irradiation.
Arylamine N-acetyltransferases (EC 2.3.1.5) are conjugating drug-metabolizing enzymes and consist of two major isozymes, NAT1 and NAT2. As they have different substrate specificity and expression of polymorphism, distribution of the isozymes may be detected by investigating acetylation. p-Aminobenzoyl glutamic acid (pABG), one of the specific substrates for NAT1 in human pro-monocytic cell-line, was metabolized through acetylation by 9000 x g supernatant fraction from human epidermal keratinocytes and the effect of ultraviolet B (UVB) irradiation on the acetylation was also studied. Forty-eight hours after irradiation of UVB (200 J/m2), the activity was not increased (114 +/- 8.3%, n = 3), while increase in N-acetylating capacity for 2-aminofluorene (substrate for NAT1 and NAT2) amounted to 201 +/- 16% (n = 3). These results suggest that there are at least two isozymes for N-acetylation in the human epidermic and NAT2 may be affected by UVB irradiation.
Kawakubo
Y
Y
Department of Dermatology, Tokai University School of Medicine, Kanagawa, Japan. kawakubo@is.icc.u-tokai.ac.jp
Ohkido
M
M
D000107:Acetylation; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism* / Q000528:radiation effects; D002478:Cells, Cultured; D000078404:Epidermal Cells; D004817:Epidermis / Q000201:enzymology*; D005971:Glutamates / Q000032:analysis / Q000378:metabolism / Q000528:radiation effects; D006801:Humans; D007700:Kinetics; D013997:Time Factors; D014466:Ultraviolet Rays
D005971:Glutamates; C011398:4-aminobenzoylglutamic acid; D001191:Arylamine N-Acetyltransferase; C016195:N-acetylglutamic acid